smell sth burn/burned/burning/being burned

[Sitifan]

1. He smelled something burn.
2. He smelled something burned.
3. He smelled something burning.
4. He smelled something being burned.

Which of the above sentences is NOT ACCEPTABLE?
_________________
Thank you very much for your reply.

[Mister Micawber]

.
I am only happy with these:

2. He smelled something burnt.
3. He smelled something burning.
.
_________________
Native English teacher at Mister Micawber's